There are several methods known in the art by which diol esters may be converted to the more useful diols. Aqueous base hydrolysis is unacceptable in that it involves the formation of salts, which must be further treated for recovery of their valuable components.
In copending applications of Will Dockery Merritt, Jr., Ser. No. 365,230 filed May 30, 1973, now abandoned, and John E. Corn et al, Ser. No. 365,239, filed May 30, 1973, now U.S. Pat. No. 3,880,939, assigned to the same assignee as this invention, processes involving alcoholysis of diol esters promoted by acidic ion exchange resins and alkali metal hydroxides, respectively, are disclosed. The liquid phase diol transesterification of dimethyl terephthalate and ethylene glycol promoted by magnesia (Torraco and Turreziani, Chim, Ind. (Milan), 44, 483-8 (1962) has also been described.